Fair Value Measurements - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended
	Aug. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchase of convertible debt security	$ 15,000,000	$ 15,000,000
Available-for-sale debt security		$ 15,000,000
Contractual maturity date		Aug. 18, 2018
Gains or losses recognized		$ 0	$ 0
TowerSec Ltd. [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		27,700,000		$ 27,700,000
Red Bend Ltd. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		30,000,000
Red Bend Ltd. [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		30,000,000		18,400,000
Southern Vision Systems Inc [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		10,000,000
Payment towards contingent consideration liability		2,100,000
Southern Vision Systems Inc [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		900,000		3,000,000
Duran Audio BV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment towards contingent consideration liability		100,000
Duran Audio BV [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		$ 1,500,000		1,600,000
IPSG/VFX [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability				$ 0